Device for positioning disk-shaped objects

ABSTRACT

A device for positioning disk-shaped objects ( 1 ) to inspect the front and rear sides of disk-shaped objects and to reduce the negative effect of large-area contact between the holder and the disk-shaped object. The device comprises a rotatable table ( 24 ) which can be adjusted in the x-y direction in an adjustment plane and is intended to accomodate a platform ( 3 ). A fork-shaped frame ( 8 ) is mounted on the platform so as to be rotatable about an axis of rotation which is aligned perpendicular to the surface of the platform ( 3 ) and the angle of tilt of which can be set relative to the adjustment plane. At its fork ends, the fork-shaped frame ( 8 ) has another axis of rotation which is aligned perpendicular to the axis of rotation of the fork-shaped frame ( 8 ) and about which a frame-shaped object holder ( 9 ) is mounted so as to be rotatable in the fork-shaped frame ( 8 ) for the purpose of turning the object. The frame-shaped object holder ( 9 ), which carries the object in the edge region of the latter, surrounds a center through which passes a pivoting axis aligned parallel to the adjustment plane and intended for setting the angle of tilt of the second axis of rotation relative to the adjustment plane. Devices of this kind can be used to position flat objects in space for purposes of inspecting semiconductor wafers or flat panels.

This application claims the benefit of the earlier filed InternationalApplication No. PCT/US01/15193, International Filing Date, May 10, 2001,which designated the United States of America, and which internationalapplication was published under PCT Article 21(2) as WO Publication No.WO 01/96836 A1.

BACKGROUND OF THE INVENTION

a) Field of the Invention

The invention relates to a device for achieving different tilt angles ofplanar objects relative to a reference plane and rotation of the objectabout an axis aligned perpendicular to the surface of the object.Devices of this kind can be used to position flat objects and, inparticular, for purposes of inspecting substrates, such as semiconductorwafers or flat panels.

b) Description of the Related Art

Technical solutions known hitherto operated on the basis of athree-dimensionally adjustable receiving element for the semiconductorwafers to be inspected, said element being provided with a vacuumsuction device serving to hold the wafer. The receiving element holdsthe semiconductor wafer during the inspection process and, by virtue ofits construction, allows rotary motion at different angles of tiltrelative to the illumination beam path or direction of inspection.

In a known positioning system of this kind as disclosed, for example, inU.S. Pat. No. 5,096,291, use is made of a holder which is mounted in anarticulated manner to allow it to perform the movements. Actuatingelements in the form of tappets transmit the movements to the holderfrom a ring, the angle of tilt of which can be adjusted and which iscoupled concentrically to a rotatable spindle.

All solutions which operate with the aid of a vacuum suction device havethe disadvantage that viewing from the rear is severely limited.

When the semiconductor wafer is held by largely surface-type contact ashitherto, migration can have an unwanted disruptive effect on theintended wafer properties. Moreover, more recent technologicalrequirements mean that the semiconductor wafer must only be brought intocontact with holding elements in a narrowly defined edge region. Theentire rear area is also unsuitable as a contact area.

The system known from U.S. Pat. No. 5,096,291 also entails a furtherrestriction due to the use of tappets, which allow only a limited rangeof motion to be achieved by the holder.

OBJECT AND SUMMARY OF THE INVENTION

It is the primary object of the invention to increase productivity inthe inspection of the front and rear sides of disk-shaped objects and toreduce the negative effect of large-area contact between the holder andthe disk-shaped object on the material properties of the disk-shapedobject.

According to the invention, the object is achieved by a device forpositioning disk-shaped objects.

The device comprises a table which can be adjusted in the x-y directionin an adjustment plane, can be rotated about a first axis of rotationaligned perpendicular to the adjustment plane and is intended to receivea platform. A fork-shaped frame is mounted on the platform in such a wayas to be rotatable about a second axis of rotation, which is alignedperpendicular to its surface and the angle of tilt of which can be setrelative to the adjustment plane. At its fork ends, the fork-shapedframe has a third axis of rotation, which is aligned perpendicular tothe second axis of rotation and about which a frame-shaped object holderis mounted in such a way as to be rotatable in the fork-shaped holderfor the purpose of turning the object. The frame-shaped object holder,which carries the object in the edge region of the latter, surrounds acenter through which passes a pivoting axis aligned parallel to theadjustment plane and intended for setting the angle of tilt of thesecond axis of rotation relative to the adjustment plane.

The table which can be adjusted in the x-y direction in the adjustmentplane ensures that object transfer to the frame-shaped object holder cantake place in an accurately fitting manner while avoiding anydisplacement of the object on supporting elements. A positive effect isfurthermore exerted on productivity since it is possible to eliminateworking steps such as prealignment of the object and devices requiredfor this purpose.

A stable base for rotation of the object is created by means of anarcuate guide in which the platform is mounted for the purpose ofsetting the angle of tilt relative to the table. A mounting, achievablewell below the object, can thereby be separated in a simple manner fromthe region of the object supported and thereby protected from particles.Since the pivoting axis of the arcuate guide, said axis being alignedparallel to the adjustment plane, passes through the center of theframe-shaped object holder, the tilting of the platform is associatedwith tilting of the object in the same way.

Rotation about the first axis of rotation can also be performed in avery stable manner a long way below the object and allows simpleadaptation of the device to the handling direction of a higher-ordersystem.

The rotary drive for the fork-shaped frame, with the aid of which driverotation of the object about its mid-perpendicular can be achieved, canalso be positioned a long way below the object and in an economicalmanner. Said mid-perpendicular can be set to all required angles inspace by rotation of the fork-shaped frame, tilting of the platform andhence of the object relative to the adjustment plane and rotation of thetable superimposed on these movements.

The single drive provided for turning the object through 180° can beenclosed with little outlay. Fundamentally, the object can be turned inall positions and even while the object is being rotated.

The frame-shaped object holder is provided with clamping devices,between which the edge region of the object is clamped when held, theclamping devices comprising rests for the edge region andcontact-pressure elements which can be adjusted toward the object topress the edge region of the object against the rests and away from theobject to release the clamping devices. It is advantageous if, to allowadjustment of each contact-pressure element, each contact-pressureelement is secured on a spring element which is provided on theframe-shaped object holder, is prestressed toward the object to be heldand on which a tension element that can be actuated to release theclamping device engages. Particularly suitable as a tension element areclamped-in wires made of a shape memory alloy which shorten in lengthwhen heated. It is possible to heat the wires in a simple manner byconnecting the wires into an electric circuit. It is also advantageousif, to reduce the areas of contact with the object to be held, the restsand the contact-pressure elements have curved surfaces which, in theclamping condition, engage on chamfered edges of the edge region of theobject and if each clamping device is provided with a sensor on theframe-shaped object holder to detect the clamped and unclamped conditionof the object. The frame-shaped object holder furthermore comprises anopen region for handler access to feed in and remove an object.

The particular advantages of the frame-shaped object holder are that notroublesome illumination shadows or hindrances to viewing in the area ofinterest arise at the object in the case of an inspection. The objectdoes not make surface contact anywhere but makes only point contact withits oblique edge on the arched rests, which are composed of inertmaterial and do not leave any traces of scratching. Since the clampingdevices engage on the object in the regions in which no structuring isprovided in the production process, the object can be seen almostcompletely and from both sides. By means of a sufficiently large numberof clamping devices, it is possible to ensure that any notches or flatswhich may coincidentally be present in the clamping region do not leadto any significant loss of clamping.

The invention is explained more fully with reference to the schematicdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 shows a system of axes of motion used in the positioning deviceunder consideration,

FIG. 2 shows the positioning device with an object which is situated ina horizontal position,

FIG. 3 shows the positioning device in a perspective representation frombelow,

FIG. 4 shows the positioning device in a rear view, in which the objectis tilted,

FIG. 5 shows a basic diagram relating to detection of the position ofthe object,

FIG. 6 shows the positioning device in a perspective representation fromthe front and from above, in which the object is tilted,

FIG. 7 shows an encased frame-shaped object holder,

FIG. 8 shows a detail of the opened object holder, and

FIG. 9 shows a circuit diagram for the purpose of explaining theoperation of the object holder.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The diagram in FIG. 1 illustrating the axes of motion is intended toclarify how a disk-shaped object 1, e.g. a semiconductor wafer or a flatpanel, can be positioned in space with the device under considerationfor the purposes of inspection.

For the object 1, which can be turned about a turning axis W forinspection of the front and rear, provision is firstly made for rotationabout an axis of rotation 8 passing through the center M of the object 1and corresponding in the inspection position illustrated to themid-perpendicular to the object 1. In the case of the semiconductorwafer used in the present example, the turning axis W extends along itsdiameter. The turning axis 8 can be tilted at different angles of tiltrelative to a vertical z axis of a reference system along a circular arcB by means of a pivoting movement. The associated pivoting axis likewisepasses through the center M and is aligned parallel to an adjustmentplane X-Y, which occupies a horizontal position in the reference system.In the position shown in FIG. 1, the pivoting axis coincides with theturning axis W. With the device under consideration, a rotary motionabout the z axis and translatory X-Y movements in the adjustment planeX-Y can furthermore be superimposed on the adjustments about the turningaxis W, the axis of rotation 8 and the setting of their tilting relatingto the vertical z axis and hence to the adjustment plane X-Y.

The positioning system illustrated thus far by means of an axis modelwill now be explained in its structural configuration.

In the positioning device in accordance with FIG. 2, the object 1 in theform of a semiconductor wafer to be positioned is in a position in whichboth supply and removal of the object 1 can take place. In thishorizontal position, in which the object 1 is aligned parallel to theadjustment plane X-Y, the axis of rotation 8 and the vertical z axis ofthe reference system coincide.

A X-Y-φ table 2, which can be adjusted in the adjustment plane X-Y androtated about the z axis, carries a platform 3, the angle of tilt ofwhich relative to the adjustment plane X-Y can be set by a pivotingmotion about a pivoting axis S by means of an arcuate guide.

For this purpose, guide tracks 4, 5, in which the platform 3 is guidedwith the aid of slides 6, 7, are secured on the X-Y-φ table 2. Afork-shaped frame 8, which is mounted on the platform 3 in such a way asto be rotatable about an axis aligned perpendicular to the surface ofthe platform 3 and corresponding to the 8 axis, acts as a carrier for aframe-shaped object holder 9. The frame-shaped object holder 9 surroundsa center M′ which coincides, in the case of the object 1 underconsideration, with the center M of the latter. At its fork ends, thefork-shaped frame 8 contains bearing and drive elements 10, 11, by meansof which the frame-shaped object holder 9 is mounted rotatably about anaxis corresponding to the turning axis W. The rotation of theframe-shaped object holder 9 is provided to enable the object 1 to beturned for inspection on both sides. The fork-shaped frame 8 iscorrespondingly wide. The pivoting axis S aligned parallel to theadjustment plane X-Y passes through the center M′, with the result thatthe object 1 too is tilted relative to the adjustment plane X-Y by thepivoting motion. If the object 1 is a semiconductor wafer, as in thepresent example, the pivoting axis S coincides with the diameter of thesemiconductor wafer.

The view of the positioning device from below in accordance with FIG. 3shows to a large extent the components of the X-Y-φ table 2 and itsdrive means. A positioning plate 16, which can be displaced in the x andy directions on roller bearings 13, 14, 15 is provided on a base plate12 fixed to the stand. Servomotors 17 and 18 for the x direction and they direction respectively are secured on the positioning plate 16. Powertransmission is provided by drive spindles 19, 20, the spindle nuts ofwhich are formed by the rotors of the servomotors 17, 18. The drivespindles 19, 20 are fixed by means of fixing devices 21, 22 and coupledto the base plate 12 with the aid of leaf spring couplings. Of the leafspring couplings, only that denoted by 23 and located on the drivespindle 19 for adjustment in the x direction can be seen. Finally, atable plate 24 is mounted on the positioning plate 16 in such a way asto be rotatable about the z axis by means of bearings (not shown), thepower produced by a drive motor 25 being transmitted to the rotatabletable plate 24 by means of a toothed-belt drive (likewise not shown). Ifone of the servomotors 17, 18 is put into operation, the positioningplate 16 and the respective servomotor 17 or 18 are displaced relativeto the base plate 12. The leaf springs of the leaf spring couplings eachhave a stabilizing effect in a perpendicular direction to the respectivedirection of displacement.

Since the positioning plate 16 is free to move relative to the baseplate 12 apart from the effects of the leaf spring couplings, transportfixings 26 are provided for transportation, by means of which bothplates 12, 16 can be connected to one another.

Underneath the platform 3 there is a drive motor 27 (see FIG. 4) for thefork-shaped frame 8 and a drive motor 28 (see FIG. 2, and not shown inFIG. 4 for the sake of clarity) for the arcuate guide. The object 1 isadditionally shielded from particles with respect to both motors 27, 28,which, like the associated gear and guide elements, are enclosed, by abowl-like part 29 (see FIG. 4, and not shown in FIG. 2 for the sake ofclarity).

The part 29 furthermore serves as a fixing element for six sensors 30,31, 32, 33, 34 and 35 for detecting the position of the object 1 as itis fed to the positioning device, in particular as it is transferred tothe frame-shaped object holder 9 with the aid of a handling arm (notshown). Corresponding openings in the part 29 allow a clear view of theobject 1. Of the sensors, only four, denoted by 30, 31, 34 and 35, canbe seen in FIG. 4. The other sensors 32 and 33 can be seen in the basicillustration in FIG. 5, with the aid of which the alignment of thepositioning device relative to the object 1 to be fed in will bedescribed in greater detail.

Referring to FIG. 5, for the alignment process, the servomotors 17 and18 provided on the X-Y-φ table 2 for the adjustment in the x and ydirections are connected to control devices 36, 37, which are connectedto outputs of a unit 38 for determining positioning vectors. The inputsof the unit 38 are coupled to the sensors 30, 31, 32, 33, 34 and 35.

Once the object 1 has been positioned above the frame-shaped objectholder 9, which is in a horizontal position, the deposition points ofthe object 1 relative to the required feed position are determined withthe aid of the sensors 30, 31, 32, 33, 34 and 35. From these, the unit38 calculates positioning vectors pointing in the opposite direction tothe respective deposition point for the purpose of determiningcorresponding manipulated variables for the servomotors 17 and 18 in thecontrol devices 36, 37. This results in adjustment of the X-Y-φ table 2in the adjustment plane X-Y. This process is continued until none of thesensors 30, 31, 32, 33, 34 and 35 can detect the presence of the object1 in its detection range. The positioning device has been moved into thefeed position relative to the object 1.

To tilt the platform 3 with the aid of the arcuate guide, a tiltingdrive is provided, as shown in FIG. 6, and, in this tilting drive, thedrive motor 28 is connected to a spindle drive 39, which adjusts a stud40 along a linear guide 42 in the direction indicated by 41. Seated onthe stud 40 is a sleeve 44 which can be displaced vertically in thedirection of the arrow 43 and engages on the platform 3 by means of arotatably mounted driver element 45. If the stud 40 is moved indirection 41, the platform 3 is pivoted on the arcuate guide. Since theplatform 3 assumes different vertical positions during the pivotingmotion owing to its connection to the arcuate guide, height compensationis required during power transmission at the linear drive. This is thepurpose of the sleeve 44 displaceable on the stud 40 and of therotatable mounting of the driver element 45.

For the particular case under consideration of the holding of asemiconductor wafer, the frame-shaped object holder 9 illustrated indetail in FIGS. 7 and 8 is of annular design and contains an open region46 for handler access to feed in and remove the object 1. Eight clampingdevices 47 are distributed along the circular ring in such a way thatthey lie opposite one another in four pairs. The number of individualholders ensures reliable holding of the object 1, even if one of theclamping devices 47 remains inoperative because of the particular shapeof the object 1. To hold the object 1, vertically adjustable rests 48lying in a common deposition plane are attached to an angled supportingbody 49 in such a way that they project into the space enclosed by thecircular ring. The rests 48 are composed of inert material and have anarched surface, with the result that there is only point contact withthe edge region of an object 1 resting on them. The object holder 9should hold the objects 1 only in an edge region which is not intendedfor the formation of structured areas in the production process. It isadvantageous if the object 1 rests on one of two mutually oppositechamfers in the edge region. The other chamfer is provided for contactwith ball-shaped contact-pressure elements 50, likewise composed ofinert material; ceramics or sapphire. The contact-pressure elements 50immobilize the object 1, with an area below their diameter pressing theobject 1 against the point rests 48. The necessary contact-pressureforce is produced by leaf springs 51 which are secured at one end onfirst holding pedestals 52 and are preloaded in the direction of theobject 1 to be immobilized by the clamping between the rests 48 and thecontact-pressure elements 50. The contact-pressure elements 50 aresecured on the other, freely movable end of the leaf spring 51. Thecounter force required to cancel immobilization is produced with the aidof tension elements which engage on the leaf springs 51 via levers 53pointing away from the object 1 to be clamped. The tension elements aredesigned as wires 54 composed of a shape memory alloy. For reasons ofsecurity, the wires 54 are present as a double pair, with the resultthat a defect in a single wire does not lead to failure of a clampingdevice 47. One end of each of the wires 54 is clamped to the lever 53,and the other end is clamped to second holding pedestals 55. The holdingpedestals 52 and 55 are secured on a printed circuit board 56 and, likethe leaf spring 51 and the wires 54, are manufactured from conductivematerial. For reasons of cleanliness, the angled supporting body 49 isclosed off at the top together with the printed circuit board 56 mountedon it by a sectional closure ring 57 which, to partition off the object1 from the printed circuit board 56, has openings only for the rests 48and the contact-pressure elements 50.

The tensile force is made to act in the wires 54 by heating resultingfrom a supply of electric current, whereupon the wires 54 shorten, withthe result that the leaf springs 51 are pulled back away from the object1 together with the contact-pressure elements 50. This actuation doesnot require any supports and is therefore completely free from theproduction of particles in the vicinity of the object 1.

FIG. 9 illustrates, in a diagram, the action of the eight clampingdevices 47. Circuit components 58 connected in series represent theclamping devices 47, each of the four resistors 59 which it containscorresponding to one of the wires 54. The overall unit made up of thecircuit components 58 is fed with a constant current by a power source60. A voltage meter 61 is used to measure a total increased voltagedrop, which occurs in the event of a malfunction. This can occur if adefect occurs in one of the wires 54. If, beyond this tolerable case ofa defect in a single wire, both pairs of wires are interrupted, a diodeshunt 62 assumes the conducting function, with the result that totalfailure of all the clamping devices 47 is prevented and the currentoperation of releasing clamping is assured.

As seen in FIG. 8, sensors 63 in conjunction with angled leaf spring endpieces 64 on the freely movable ends of the leaf springs 51 are used todistinguish between the states of clamping and release of the object 1,in which the clamping devices 47 may be. Owing to the differentdeflections of the leaf spring end pieces 64 in the two states, thesensors 63 are unactuated in the state of clamping while, in the stateof release, the leaf spring end pieces 64 project into the detectionzones of the sensors 63 to form a signal. The ball-shapedcontact-pressure elements 50 are additionally provided with a securingelement, in the present example in the form of a cylindrical pin 65which projects from the contact-pressure element 50 in the direction ofthe object 1 and, in normal operation does not touch the object 1. Thecylindrical pin 65 prevents the object 1 from pushing the leaf spring 51out beyond the ball wedge formed to such an extent that the object canfall out when there is a non-nominal impact effect during inspection ofthe rear side. The leaf springs 51 are dimensioned in such a way thatnormal upside down operation is no problem.

While the foregoing description and drawings represent the presentinvention, it will be obvious to those skilled in the art that variouschanges may be made therein without departing from the true spirit andscope of the present invention.

1. A device for positioning substantially planar objects comprising: atable which can be adjusted in the x-y direction in an adjustment plane,can be rotated about a first axis of rotation aligned perpendicular tosaid adjustment plane and is intended to receive a platform; saidplatform having a surface and a second axis of rotation, which isaligned perpendicular to said surface and an angle of tilt of which canbe set relative to said adjustment plane; a fork-shaped frame which ismounted on said platform in such a way as to be rotatable about saidsecond axis of rotation; a frame-shaped object holder for an object forcarrying said object in an edge region of the object and surrounds acenter through which passes a pivoting axis aligned parallel to saidadjustment plane and intended for setting said angle of tilt of saidsecond axis of rotation relative to said adjustment plane; saidfork-shaped frame having fork ends with a third axis of rotation, whichis aligned perpendicular to said second axis of rotation and about whichsaid frame-shaped object holder is mounted in such a way as to berotatable in said fork-shaped frame for the purpose of turning saidobject.
 2. The device according to claim 1, wherein, for the purpose ofsetting the angle of tilt relative to said adjustment plane, saidplatform is mounted in an arcuate guide, the pivoting axis of which isaligned parallel to said adjustment plane and passes through said centerof said frame-shaped object holder, the tilting of said platform therebybeing associated with tilting of said object in the same way.
 3. Thedevice according to claim 2, wherein said frame-shaped object holder isprovided with clamping devices, between which said edge region of saidobject is damped when held.
 4. The device according to claim 3, whereinsaid clamping devices comprising rests for said edge region andcontact-pressure elements which can be adjusted toward said object topress said edge region of said object against said rests and away fromsaid object to release said clamping devices.
 5. The device according toclaim 4, wherein, to allow adjustment of each contact-pressure element,each contact-pressure element is secured on a spring element which isprovided on said frame-shaped object holder, is prestressed toward saidobject to be held and on which a tension element that can be actuated torelease said clamping device engages.
 6. The device according to claim5, wherein said tension element is formed by clamped-in wires made of ashape memory alloy which shorten in length when heated.
 7. The deviceaccording to claim 6, wherein said wires are connected into a circuit toallow heating.
 8. The device according to claim 7, wherein, to reducethe areas of contact with said object to be held, said rests and saidcontact-pressure elements have curved surfaces which, in the clampingcondition, engage on chamfered edges of said edge region of said object.9. The device according to claim 8, wherein said frame-shaped objectholder comprises an open region for handler access to feed in and removean object.
 10. The device according to claim 9, wherein each clampingdevice is provided with a sensor on said frame-shaped object holder todetect the clamped and unclamped condition of said object.
 11. Asemiconductor object positioning device for holding and moving asubstantially planar semiconductor object that has opposite planar sidesdefining a thickness of the object therebetween, the device comprising:an object holder comprising a center through-hole which is sized andshaped for receiving the object such that opposite planar sides of theobject are substantially entirely visible at opposite sides of theobject holder, the object holder further comprising a clamping elementoperable to exert a compressive force across the thickness of theobject; and a movement mechanism for moving the object holder, themovement mechanism comprises a drive connected to the object holder forflipping orientation of the object holder and the object held by theobject holder about 180°.
 12. A device as in claim 11 wherein the objectholder comprises a general ring shape with one open section through thering shape.
 13. A device as in claim 11 wherein the object holdercomprises rests which extend into the through-hole and contact elementsmovable into and out of the through-hole to clamp portions of the objectat an outer perimeter of the object between the rests and contactelements, wherein the contact elements are independently movablerelative to the rests.
 14. A device as in claim 11 wherein the movementmechanism comprises a fork-shaped frame member having the object holderrotatably connected to ends of opposite arms of the fork-shaped framemember.
 15. A semiconductor object positioning device for holding andmoving a substantially planar semiconductor object, the devicecomprising: an object holder comprising a frame with a receiving areawhich is sized and shaped for receiving the object; a movement mechanismconnected to the object holder for moving the object holder; and sensorsconnected to the movement mechanism at a first side of the object holderand having sensor paths through the receiving area for sensing an outerperimeter of an object being held on an opposite second side of theobject holder and awaiting positioning into the receiving area, whereinthe movement mechanism moves the object holder, based upon input fromthe sensors, to a predetermined position relative to the object forreceiving the object at a predetermined position in the receiving area.16. A device as in claim 15 wherein the sensors are optical sensorsconnected to a bottom side of a bowl shaped member located beneath theobject holder, the sensor paths extending through holes in the bowlshaped member.
 17. A semiconductor object positioning device for holdingand moving a substantially planar semiconductor object, the devicecomprising: a general ring shaped object holder; a fork-shaped framemember connected to the object holder for flipping orientation of theobject holder; and an arcuate guide for tilting the fork-shaped framemember relative to a support table, the arcuate guide comprising arcuateshaped guide tracks connected to the support table and slides connectedto the fork-shaped frame member, the slides having recesses with theguide tracks slidably located in the recesses.
 18. A device as in claim17 wherein the object holder comprises a general ring shaped frame withan opening gap through a side section of the general ring shape.
 19. Adevice as in claim 17 further comprising a motor for rotating thefork-shaped frame member.
 20. A semiconductor object holder for holdinga substantially planar semiconductor object, the holder comprising: aframe having a receiving area for receiving the object; and contactelements movably connected to the frame between an inward position intothe receiving area and an outward position out of the receiving area,wherein, when the contact elements are located in their inwardpositions, the contact elements are adapted to clamp portions of theobject between bottom surfaces of the contact elements and top surfacesof rests on the frame in the receiving area.
 21. A holder as in claim 20further comprising a printed circuit board located within the frame. 22.A holder as in claim 21 further comprising movement members connectedbetween the frame and the contact elements for moving the contactelements, the movement members comprising shape memory alloy.
 23. Aholder as in claim 20 wherein the contact elements are connected to theframe by leaf springs.
 24. A holder as in claim 23 further comprisingsensors which are directly actuated by portions of the leaf springs. 25.A holder as in claim 20 wherein the contact elements are movably mountedto the frame by springs and the holder further comprises tensioningmembers to move the contact elements and deflect the springs.
 26. Aholder as in claim 25 wherein the tensioning members comprise shapememory alloy and the holder further comprises a heater for heating thetensioning members.
 27. A device for gripping a substantially planarobject comprising: a frame for holding the substantially planar objectat a predetermined position having a center location; a rest dependingfrom the frame and disposed for simultaneously supporting a bottomsurface of an edge region of the object on opposite sides of the object;and an element movably connected to the frame and moveable in a firstdirection from a first position to a second position relative to therest for substantially simultaneously contacting a top surface of theedge region of the object on opposite sides of the object, wherein therest and the element operate to effect top to bottom pinching of theedge region to secure the edge region of the object between the rest andthe element, and wherein the rest is substantially fixed in the firstdirection relative to the center location defined by the frame.
 28. Thedevice of claim 27, wherein the edge region comprises a first chamferincluding the first surface and a second chamfer including the secondsurface, and wherein the first and second chamfers are mutuallyopposite.
 29. The device of claim 27, wherein the edge region is free ofstructured areas formed during a production process.
 30. The device ofclaim 27, wherein the rest includes a curved surface such that there issubstantially a point contact between the rest and the first surface.31. The device of claim 27, wherein the rest is adjustable in adirection perpendicular to a first plane of the object.
 32. The deviceof claim 27, wherein the element includes a curved surface such thatthere is substantially a point contact between the element and thesecond surface.
 33. The device of claim 27, wherein the element has agenerally spherical shape that presses the object against the rest. 34.The device of claim 27, wherein the element comprises a pressure contactportion having a diameter parallel to a second plane of the object. 35.The device of claim 27, further comprising a spring element for biasingthe element toward the object and for causing the contact pressureelement to apply pressure to the second surface.
 36. The device of claim35, wherein the spring element is a leaf spring.
 37. The device of claim27, further comprising a tension element for pulling the element awayfrom the object and for causing the element and the rest to release theedge region.
 38. The device of claim 37, wherein the tension elementfurther comprises a shape memory alloy wire that contracts to pull theelement away from the object.
 39. The device of claim 37, furthercomprising a sensor for sensing whether the edge region of the objecthas been secured or released.
 40. The device of claim 39, wherein thesensor senses a position of the spring element and generates a signalwhen the edge region is released.
 41. A method for gripping the edge ofa substantially planar object comprising: providing a frame for holdingthe substantially planar object at a predetermined position having acenter location; supporting a bottom surface of an edge region of theobject with a rest depending from the frame, the rest being disposed tosimultaneously support the bottom surface of the edge region on oppositesides of the planar object; and contacting a top surface of the edgeregion with an element movably connected to the frame, the element beingarranged to substantially simultaneously contact the top surface of theedge region on opposite sides of the planar object, wherein thesupporting and contacting actions effect pinching the top to bottomsurfaces of the edge region to secure the edge region of the objectbetween the rest and the element and wherein contacting the top surfacecomprises moving the element in a first direction relative to the centerlocation defined by the frame, wherein the rest is substantially fixedin the first direction relative to the center location defined by theframe.
 42. The method of claim 41, wherein the edge region comprises afirst chamfer including the first surface and a second chamfer includingthe second surface, and wherein the first and second chamfers aremutually opposite.
 43. The method of claim 41, wherein supporting thefirst surface and contacting the second surface includes providing apoint contact with the first and second surfaces, respectively.
 44. Themethod of claim 41, further comprising: utilizing a contact pressureelement for contacting the second surface; and biasing the contactpressure element toward the object causing the contact pressure elementto apply pressure to the second surface.
 45. The method of claim 44,further comprising pulling the contact pressure element away from theobject causing the contact pressure element to release the edge region.46. The method of claim 45, further comprising sensing whether the edgeregion of the object has been secured or released and generating asignal upon release of the edge region.
 47. A clamping device comprisinga frame for holding a planar object at a predetermined position, theclamping device further comprising a plurality of gripping surfacesconnected to the frame, at least a first of which is movable in a firstdirection to pinch an edge region thickness of a planar object betweenat least the first gripping surface and a second of the plurality ofgripping surfaces to secure the edge region of the object, wherein thesecond of the plurality of gripping surfaces is fixed in the firstdirection relative to the center location defined by the frame; andwherein the second gripping surface is disposed to simultaneouslysupport a bottom surface of an edge region on opposite sides of theobject, and wherein the first gripping surface is arranged tosubstantially simultaneously contact a top surface of the edge region onopposite sides of the object, wherein the top surface of the edge regionopposes the bottom surface of the edge region.
 48. The clamping deviceof claim 47, wherein at least the first and second gripping surfaces arecurved to provide a substantially point contact with the edge region ofthe object.
 49. The clamping device of claim 47, further comprising aspring element for biasing the first gripping surface in a directiontoward and parallel to the object causing the first gripping surface toapply pressure to the edge region.
 50. The clamping device of claim 47,further comprising a tension element for pulling the first grippingsurface in a direction away from and parallel to the object causing thefirst gripping surface to release the edge region.
 51. The clampingdevice of claim 50, further comprising a sensor for sensing whether theedge region of the object has been secured or released and forgenerating a signal when the edge region is released.
 52. A device forpositioning a substantially planar object comprising: a holder forcarrying the object, the holder being adapted to hold the object at apredetermined position relative to the holder; and a clamping deviceconnected to the holder, the clamping device including: a rest forsimultaneously supporting a bottom surface of an edge region of theobject on opposite sides of the object; and an element movably connectedto the holder and moveable in a first direction from a first position toa second position for substantially simultaneously contacting a topsurface of the edge region of the object on opposite sides of theobject, wherein the top surface of the edge region is opposed to thebottom surface of the edge region, and wherein the rest and the elementoperate to effect top to bottom pinching of the edge region to securethe edge region of the object between the rest and the element; whereinthe rest is substantially fixed in the first direction relative to thepredetermined position.
 53. The device of claim 52, wherein the edgeregion comprises a first chamfer including the first surface and asecond chamfer including the second surface, and wherein the first andsecond chamfers are mutually opposite.
 54. The device of claim 52,wherein the edge region is free of structured areas formed during aproduction process.
 55. The device of claim 52, wherein the restincludes a curved surface such that there is substantially a pointcontact between the rest and the first surface.
 56. The device of claim52, wherein the rest is adjustable in a direction perpendicular to afirst plane of the object.
 57. The device of claim 52, wherein theelement includes a curved surface such that there is substantially apoint contact between the element and the second surface.
 58. The deviceof claim 52, wherein the element has a generally spherical shape thatpresses the object against the rest.
 59. The device of claim 52, whereinthe element comprises a pressure contact portion having a diameterparallel to a plane of the object.
 60. The device of claim 52, furthercomprising a spring element for biasing the element toward the objectand for causing the contact pressure element to apply pressure to thesecond surface.
 61. The device of claim 60, wherein the spring elementis a leaf spring.
 62. The device of claim 52, further comprising atension element for pulling the element away from the object and forcausing the element and the rest to release the edge region.
 63. Thedevice of claim 62, wherein the tension element further comprises ashape memory alloy wire that contracts to pull the element away from theobject.
 64. The device of claim 62, further comprising a sensor forsensing whether the edge region of the object has been secured orreleased.
 65. The device of claim 64, wherein the sensor senses aposition of the spring element and generates a signal when the edgeregion is released.